Microsoft very quickly responded to the speculative execution side-channel vulnerabilities also called Meltdown and Spectre which affect many modern processors and operating systems, including chipsets from Intel, AMD, and ARM. Microsoft released some guidance how you should protect your devices against these vulnerabilities. The Microsoft Security Defense Team also published an article with guidance and more details on this: ADV180002 | Guidance to mitigate speculative execution side-channel vulnerabilities

In this blog post I tried to quickly summarize the information and link it to the right websites.

Summary

Microsoft is aware of detailed information that has been published about a new class of vulnerabilities referred to as speculative execution side-channel attacks. This industry-wide attack method takes advantage of out-of-order execution on many modern microprocessors and is not restricted to a single chip, hardware manufacturer, or software vendor. To be fully protected, updates are required at many layers of the computing stack and include software and hardware/firmware updates. Microsoft has collaborated closely with industry partners to develop and test mitigations to help provide protections for our customers. At the time of publication, Microsoft had not received any information to indicate that these vulnerabilities have been used to attack our customers.

Note This issue also affects other operating systems, such as Android, Chrome, iOS, and MacOS.

Warning

Microsoft addressed protect against speculative execution side-channel vulnerabilities in the latest Windows Updates. However, customers who only install the Windows January 2018 security updates will not receive the benefit of all known protections against the vulnerabilities. In addition to installing the January security updates, a processor microcode, or firmware, update is required. This should be available through your device manufacturer. Surface customers will receive a microcode update via Windows update.

Guidance for Windows Client

Customers should take the following actions to help protect against the vulnerabilities:

Verify that you are running a supported antivirus application before you install OS or firmware updates. Contact the antivirus software vendor for compatibility information.

Apply all available Windows operating system updates, including the January 2018 Windows security updates.

Apply the applicable firmware update that is provided by the device manufacturer

Windows-based machines (physical or virtual) should install the Microsoft security updates that were released on January 3, 2018. See Microsoft Security Advisory ADV180002 for updates for the following versions of Windows.

Your server is at increased risk if it is in one of the following categories:

Hyper-V hosts

Remote Desktop Services Hosts (RDSH)

For physical hosts or virtual machines that are running untrusted code such as containers or untrusted extensions for database, untrusted web content or workloads that run code that is provided from external sources.

There for Microsoft posted some additional registry keys to mitigations on servers. Microsoft also added some extra registry keys if you are running older versions of Hyper-V.

Guidance for Virtual Machines running on Hyper-V

In addition to this guidance, the following steps are required to ensure that your virtual machines are protected from CVE-2017-5715 (branch target injection):

Ensure guest virtual machines have access to the updated firmware. By default, virtual machines with a VM version below 8.0 will not have access to updated firmware capabilities required to mitigate CVE-2017-5715. Because VM version 8.0 is only available starting with Windows Server 2016, users of Windows Server 2012 R2 or earlier must modify a specific registry value on all machines in their cluster.

Perform a cold boot of guest virtual machines.Virtual machines will not see the updated firmware capabilities until they go through a cold boot. This means the running VMs must completely power off before starting again. Rebooting from inside the guest operating system is not sufficient.

Update the guest operating system as required. See guidance for Windows Server.

Guidance for Surface Devices

Microsoft will provide UEFI updates for the following devices:

Surface Pro 3

Surface Pro 4

Surface Book

Surface Studio

Surface Pro Model 1796

Surface Laptop

Surface Pro with LTE Advanced

Surface Book 2

The updates will be available for the above devices running Windows 10 Creators Update (OS version 15063) and Windows 10 Fall Creators Update (OS version 16299). You will be able to receive these updates through Windows Update or by visiting the Microsoft Download Center.

Guidance for Azure

Microsoft has already deployed mitigations across the majority of our cloud services and is accelerating efforts to complete the remainder.

However, I always recommend that you also patch your operating systems and applications to be protected against other vulnerabilities.

Impact to Enterprise Cloud Services

Microsoft is not aware of any attacks on the Microsoft Cloud customers which leverage these types of vulnerabilities. Microsoft employs a variety of detection capabilities to quickly respond to any malicious activity in our enterprise cloud services.

Most of the Azure infrastructure has already received mitigations against this class of vulnerability. An accelerated reboot is occurring for any remaining hosts. Customers can check the Azure Portal for additional details.

All other enterprise cloud services such as Office 365, Dynamics 365, and Enterprise Mobility + Security have mitigations against these types of vulnerabilities. Microsoft engineering is continuing to perform analysis across the environments to confirm further protection.

Some variations of these vulnerabilities apply also to the virtual machines (VMs) that are running in the tenant space. Customers should continue to apply security best practices for their VM images, and apply all available operating system updates to the VM images that are running on Azure Stack. Contact the vendor of your operating systems for updates and instructions, as necessary. For Windows VM customers, guidance has now been published and is available in this Security Update Guide.

Guidance for SQL Server

The following versions of Microsoft SQL Server are impacted by this issue when running on x86 and x64 processor systems:

SQL Server 2008

SQL Server 2008 R2

SQL Server 2012

SQL Server 2014

SQL Server 2016

SQL Server 2017

IA64-based versions of SQL Server 2008 are not believed to be affected.

Microsoft made a list of different SQL Server scenarios depending on the environment that SQL Server is running in and what functionality is being used. Microsoft recommends that you deploy fixes by using normal procedures to validate new binaries before deploying them to production environments.

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About

My name is Thomas Maurer. I am a Senior Cloud Advocate at Microsoft. I am part of the Azure engineering team and engage with the community and customers around the world. I am located in Switzerland. I am focusing on Microsoft technologies, especially cloud and datacenter solutions based on Microsoft Azure, Azure Stack and Windows Server. Opinions are my own.